The secrets of STOICHIOMETRY

Hello there.  You may be wondering, what Stoichiometry means.  Well:

Stoichiometry is the quantitative analysis of chemical reactions and is about measuring the amounts of substances involved in a reaction.


What??  You don't know what this means??  Well, to put it into more simple english, it is the study between the amount of reactants used in a reaction and the amounts of a products produced by a reaction.

In more simpler english, it is the study of ratios between reactants and products.


Here is a sample question of stoichiometry:

For the equation: Zn + 2HCl ---> ZnCl2 + H2

1) How many atoms of Zn are needed to produce 1 molecule of Hydrogen?
Answer: 1, because the ratio of Zn to Hydrogen is 1:1, therefore the answer is 1.


2) How many grams of Zinc Chloride will be formed when 2.00g of Hydrogen is formed?

Step 1 - Convert 2.00g of Hydrogen to moles

2.00g x 1 mol/2.0g = 1 mole of Hydrogen.

Step 2 - Plot the mole into the mole ratio.

In this case, the ratio is 1 mol ZnCl2 : 1 mol H2, because there is one mole of hydrogen.

Step 3 - Answer the question, in this case, convert the moles back into mass.

1 mol ZnCl2 x 136.4g/1mol = 136.4 g of ZnCl2

136.4g of ZnCl2 will be produced when 2.00 g of H is formed.


Still don't understand?  Watch the video to learn more!